Schedule of activities

RECAP From Soldati et al (2004) Current Opinion in Cell Biology 16,32-40. 2

ANIMAL PHYLOGENY PROTOSTOMIA BILATRERIA ANIMALIA CHORDATA HEMICHORDATA DEUTEROSTOMIA ECHINODERMATA ARTHROPODA TARDIGRADA ONYCHOPHORA NEMATODA ECDYSOZOA NEMATOMORPHA PRIAPULIDA KINORHYNCHA PROTOSTOMIA BILATRERIA ANIMALIA BRYOZOA BRACHIOPODA PHORONIDA ANNELIDA LOPHOTROCHOZOA MOLLUSCA SIPUNCULIDA PLATYHELMITHES PLACOZOA CNIDARIA PRE-BILATERIANS PORIFERA PROTISTA MODIFIED FROM Valentine et al., 1999

PROTISTA Unicellular, basal eukaryotes Pseudopods Flagella (Cilia) Apical complex Apicomplexa

Toxoplasma gondii :TOXOPLASMOSIS Human infection: A) undercooked infected meat containing Toxoplasma cysts B) ingested oocyst (fecally contaminated hands or food) C) organ transplantation or blood transfusion D) transplacental transmission The parasites form tissue cysts, most commonly in skeletal muscle, myocardium, and brain; these cysts may remain throughout the life of the host. Geographic Distribution: Cosmopolitan. High prevalence of infection in France has been related to a preference for eating raw or undercooked meat, while high prevalence in Central America has been related to the frequency of stray cats in a climate favoring survival of oocysts. The Netherlands 80-90% prevalence The overall seroprevalence in the United States 22.5%, seroprevalence among women of childbearing age (15 to 44 years) of 15%.

Toxoplasma gondii in Cats: Fecal Stages Identified as Coccidian Oocysts J. K. FRENKEL, J. P. Dubey, and N. L. Miller, Department of Pathology and Oncology, University of Kansas School of Medicine, Kansas City 66103 Isospora-type oocysts were excreted by cats following the ingestion of TOXOPLASMA from infected mice. Oocysts appeared 3 to 5 days after cysts were ingested and 8 to 10 days after trophozoites were ingested, and also 21 to 24 days after the administration of infective fecal suspensions from cats. A close quantitative and biologic correlation between oocysts and TOXOPLASMA infectivity of the feces was observed which could not be separated by density gradient centrifugation and filtration methods. TOXOPLASMA is an intestinal coccidian of cats which is fecally spread. It has evolved to multiply in brain and muscle and in other species, making it possible for carnivorism to become another means of transmission. Science 6 February 1970: Vol. 167. no. 3919, pp. 893 - 896 DOI: 10.1126/science.167.3919.893

http://fullmal.hgc.jp/tg/docs/toxoplasma.html

bradyzoites from tissue cyst OR sporozoites from mature oocyst OR tachyzoites from prey merogeny tachyzoites merozoites tachyzoites tachyzoites gametogony bradyzoites in cyst Sporogeny takes several days! http://animalworld.com.ua/news/Samyje-opasnyje-parazity-planety

http://www.stanford.edu/class/humbio153/SuccessfulParasite/Background.html Stages of Toxoplasma gondii. Scale bar in A-D= 20 µm, in E-G = 10 µm. A. Tachyzoites in impression smear of lung. Note crescent-shaped individual tachyzoites (arrows), dividing tachyzoites (arrowheads) compared with size of host red blood cells and leukocytes. Giema stain. B. Tissue cysts in section of muscle. The tissue cyst wall is very thin (arrow) and encloses many tiny bradyzoites (arrowheads). Hematoxylin and eosin stain. C. Tissue cyst separated from host tissue by homogenization of infected brain. Note tissue cyst wall (arrow) and hundreds of bradyzoites (arrowheads). Unstained. D. Schizont (arrow) with several merozoites (arrowheads) separating from the main mass. Impression smear of infected cat intestine. Giemsa stain. E. A male gamete with two flagella (arrows). Impression smear of infected cat intestine. Giemsa stain. F. Unsporulated oocyst in fecal float of cat feces. Unstained. Note double layered oocyst wall (arrow) enclosing a central undivided mass. G. Sporulated oocyst with a thin oocyst wall (large arrow), 2 sporocysts (arrowheads). Each sporocyst has 4 sporozoites (small arrow) which are not in complete focus. Unstained.

Toxoplasmosis Generally an asymptomatic infection in normal adults. Some (10% to 20%) patients with acute infection may develop cervical lymphadenopathy and/or a flu-like illness. The clinical course is benign and self-limited; symptoms usually resolve within a few months to a year. Tissue cysts (containing "bradyzoites" or "hypnozoites") maintain immunity Cysts can re-activate, if immune status should be compromised (AIDS). The infection is then severe and fulminant, unless treated. Fulminant is any event or process that occurs suddenly and quickly, and is intense and severe to the point of lethality, i.e., it has an explosive character. Fulminare (Latin): to strike with lightning.

Martina Navratilova Lost US-open 1982 suffered from toxoplasmosis

congenital toxoplasmosis Congenital infection, acquired by transplacental spread of the organism. Profound effects with extensive inflammatory necrotic foci in the brain, which may later calcify. Death of fetus, hydrocephalus, vision and learning problems later in life.                                               http://www.ncbi.nlm.nih.gov/books/NBK7752/ http://tmcr.usuhs.mil/tmcr/main.htm Hydrocephalus Intracranial calcification in cerebral cortex

Prevention Avoid contact with developed oocysts Sandboxes, cat litterboxes, dog noses Avoid raw/undercooked meat that has not been frozen previously Rinse vegetables Immune status (acute, chronic, old infection)

Diagnosis Observation of parasites in patient specimens, such as bronchoalveolar lavage material from immunocompromised patients, or lymph node biopsy. Isolation of parasites from blood or other body fluids, by intraperitoneal inoculation into mice or tissue culture.  Detection of parasite genetic material by PCR, especially in detecting congenital infections in utero. Serologic testing is the routine method of diagnosis, because the techniques described above are technically complex Treatment: Treatment is not needed for a healthy person who is not pregnant. Symptoms will usually go away within a few weeks.  Treatment (various antibiotics) may be recommended for pregnant women or persons who have weakened immune systems. 

JUST AN INFECTION?

PROTISTA Unicellular, basal eukaryotes Pseudopods Flagella (Cilia) Apical complex Apicomplexa 18

We knew.. Swamps (mosquitoes)/recurring fevers/death Huang Ti, 2700 BC, China: description Empedocles, 500 BC, Sicily: dried out marshes Hippocrates, 400 BC, Greece: patterns of fever Royal decree, 11th-century, Spain: Death sentence for planting rice close to villages Bad air: Mal’aria: Lagoons: Palus, paludism